DESCRIPTION: The goal of the proposed project is to determine the feasibility of developing a novel non-invasive and sensitive joint health diagnostic device capable of detecting the integrity of soft-tissue. Soft tissue knee injuries are some of the most common and clinically challenging musculoskeletal disorders seen in the emergency department. Over $10 billion is spent each year repairing soft tissue injuries in the U.S., Europe and Japan and advances over just the last fifty years have shown tremendous improvements for patients who undergo surgical reconstruction. However, there is still plenty of room for improvement as the risk of re-injury and secondary health issues remains high after reconstruction surgery. Other questions also remain such as optimal timing for surgery and the decision as to what sort of surgery or whether to undergo surgery at all exist for young people still growing. Current diagnostics are limited in tha they are expensive, only provide static images of the knee and while good at showing significant damage, are unable to accurately detect a lot of the more minor damage. Further, physical knee exams can indicate minor damage, but these tests are highly subjective, vary tremendously from person to person, and do not provide a clear indication of the joint susceptibility to injury r other minor damage that may indicate future risks. Recent advances in our understanding of the physiology of the knee and the biomechanics of the soft tissue can be coupled with developments in Acoustic Emission sensors and sophisticated signal processing to provide us a unique opportunity to develop a diagnostic tool capable of discerning microdamage related to the overall integrity of the knee. Such a novel non-invasive method could provide integral information that can be used to improve treatments and identify at risk individuals. In the proposed study, we will investigate if there are acoustic emission signal characteristics associated with a variety of health states that can be used for monitoring joint status, recovery or risk of further injury.